反应详情

A mixture of 2-(1-methyl-1H-indol-3-yl)pentanoic acid (12a) (1.22 g, 5.28 mmol) and concentrated sulfuric acid (1 mL) in methanol (40 mL) was refluxed for 3 hours. After concentration, the mixture was quenched with a saturated aqueous solution of sodium carbonate and the aqueous layer was extracted with dichloromethane (2×20 mL). The organic layer was dried over sodium sulfate, filtered and evaporated under reduced pressure. The residue was purified by flash chromatography on silica gel (cyclohexane/ethyl acetate 93/7) to afford the desired ester (12b) as a white solid (910 mg, 3.71 mmol, 70%).

1. temperaturewas refluxed for 3 hours
2. concentrationAfter concentration
3. customthe mixture was quenched with a saturated aqueous solution of sodium carbonate
4. extractionthe aqueous layer was extracted with dichloromethane (2×20 mL)
5. dry with materialThe organic layer was dried over sodium sulfate
6. filtrationfiltered
7. customevaporated under reduced pressure
8. customThe residue was purified by flash chromatography on silica gel (cyclohexane/ethyl acetate 93/7)